What is the actual meaning of this shabad in Japji Sahib?

SOCHAI SOCH NA HOW AEE JE SOCHAI LAKHVAR
In this Pauree, Guru Nanak listed four prevalent existing religious beliefs about how to realize God and then outlines his own doctrine. It is important to note that this has been a common practice adopted by all Gurus when writing Gurbani – it is important to not mistake their summary of the belief systems existing at the time to be the Gurus’ doctrine.

In this Pauree, Guru Nanak is listing a common belief that existed at the time, that by bathing in holy rivers and pools, a person’s past sins are literally washed away and the person can achieve higher consciousness. Guru Nanak says bathing in holy rivers and holy waters does not wash away the pollution of mind even if this is repeated thousands of times. Guru Nanak says “TAN DHOTAI MANN HACCHA NA HOAE” [insert page number] meaning, washing the body does not wash away evil thoughts. A person does not become spiritual by washing their body in water. Even today thousands of Sikhs bathe in the Sarovar (the water pool at Harimandir Sahib) believing that all their sins will be washed away as a result. In this Pauree, Guru Nanak is telling us that ego can not be washed with clean water. This is a worthless ritual that Sikhs (people) are doing out of ignorance.

CHUPAI CHUP NA HOWAEE JE LAAE RAHAN LIVTAR.
It was common practice for people to leave society and go to remote places, or do things like take a vow of silence in order to achieve calmness of mind, freedom from emotions, and to achieve tranquility and inner peace. Guru Nanak says here that the mind cannot be silenced jut by sitting in silence. The harder you try the more impossible it is to silence the mind. The mind is like a bird that flies in all directions all day. The mind can only be trained through Divine Wisdom to be positive and calm. In other words, it is not possible to completely silence our thoughts: instead, our focus should be to change the quality of our thoughts. The rest of the Japjee Sahib, and the Gurbani in general, teach us how to do this.

BHUKHIAN BHUKH NA UTTAREE JE BANA POORIAN BHAR.
Man thought that inner peace and bliss could be attained by amassing material wealth. What society has realized is that this is not the case. The collective mind dysfunction has resulted in more stress and mental diseases in society than ever before. In this Pauree, Guru Nanak says that material wealth can only provide comforts for the body but can never be the source of inner peace and bliss. A person can be a billionaire but not attain peace and bliss without realizing the Divine Wisdom and choosing the way of surrender to the Divine Will. It may be said that society today is gaining material goods but losing their respective souls. They are rich outside but poor inside.

SAHAS SIANPAN LAKH HOHAI TA IK NA CHALAI NAL.
Human intelligence has achieved huge successes in all areas including economics, science, medicine, art, music and other fields but attachment to material things and greed has resulted in collective unhappiness and dissatisfaction, and complete identification with ego. Guru Nanak says none of those successes can bring inner peace and joy without balancing worldly knowledge with spirituality. We are not our mind and thoughts.

KIW SACHIARA HOEEAI KIW KURAI TUTAI PAL.
Guru Nanak raises a question that if other ways have failed then what is the path to break the wall of falsehood and be truthful? How can a follower realize God?

HUQAM RAJAEE CHALNA NANAK LIKHIA NAL.
Here Guru Nanak gives the answer and lists his spiritual doctrine. Guru Nanak says the real path is to surrender to the Divine Will, i.e. the immutable laws of Nature. Guru Nanak says, EKO NAM HUQAM HAI NANAK SATGUR DEEA BHUJHAI JIO. Meaning the only path is to understand and internalize and live the teachings of SGGS.